1. Field of the Invention
This invention relates to a riding lawn mower including a front wheel unit, a rear wheel unit having a left rear wheel and a right rear wheel, a body frame supported by the front wheel unit and the rear wheel unit, a mower unit disposed under the body frame between the front wheel unit and the rear wheel unit, a driver""s seat disposed on the body frame to be above the mower unit, an engine disposed rearwardly of the driver""s seat, and a drive transmission mechanism for transmitting drive from the engine to the rear wheel unit.
1. Description of the Related Art
This type of lawn mower is known from Japanese Patent Laying-Open Publication 2000-270652, in which an engine is mounted rearwardly of rear axles and substantially level with the rear axles. This lawn mower has no bulky engine disposed forwardly of a driver""s seat. The operator has good forward visibility to facilitate a grass cutting operation with little chance of leaving uncut patches. However, for rearwardly discharging grass clippings reaped by a mower unit toward a grass catcher connected to the rear of the vehicle body and collecting the grass clippings in the grass catcher, the presence of the engine in a space between and above the right and left rear wheels prevents a space of sufficient height there. Thus, a sufficiently large grass clippings discharge area cannot be secured. A duct must be provided laterally outwardly of the vehicle body for guiding the grass clippings from the mower unit to the grass catcher, which results in an enlargement of the vehicle body. In a lawn mower known from U.S. Pat. No. 5,946,894, an engine and a driver""s seat are arranged substantially between front wheels and rear wheels, and a mower disposed below the driver""s seat. This lawn mower also has the same drawback that the presence of the engine in a space between and above the right and left rear wheels prevents a space of sufficient height there. Further, the engine and the driver""s seat arranged substantially between the front wheels and the rear wheels require an extended distance between the front wheels and the rear wheels. Thus, no consideration is made for this type of lawn mower to attach the grass catcher to the rear of the vehicle body as an addition.
The object of this invention is to provide a lawn mower for enabling full use of a space from the rear of a mower unit and between right and left rear wheels, and allowing a grass catcher to be connected to the rear of a vehicle body as necessary to collect grass clippings.
The above object is fulfilled, according to this invention, by a riding lawn mower comprising a front wheel unit, a rear wheel unit having a left rear wheel and a right rear wheel, a body frame supported by the front wheel unit and the rear wheel unit, a mower unit disposed under the body frame between the front wheel unit and the rear wheel unit, a driver""s seat disposed on the body frame to be above the mower unit, an engine disposed rearwardly of the driver""s seat, and a drive transmission mechanism for transmitting drive from the engine to the rear wheel unit, wherein the engine is disposed between and substantially at a higher level than the left and right rear wheels to secure a utility space extending longitudinally of the vehicle body between the left and right rear wheels.
In this construction, the engine is disposed above and between the left and right rear wheels. Thus, a sufficient space is secured for rearwardly throwing grass clippings cut by the mower unit. Such a space extending longitudinally of the vehicle body between the left and right rear wheels may be used for accommodating a duct that guides grass clippings cut by the mower unit rearwardly of the vehicle body. Moreover, a sufficiently reduced distance may be achieved between the front wheels and rear wheels. The reduced wheelbase, combined with the mower unit disposed substantially directly under the diver""s seat, provides an advantage of allowing the driver easily to confirm cutting areas below, which facilitates a grass cutting operation.
To fulfill the above-noted object, another lawn mower according to this invention employs a body frame extending to a region rearwardly of the rear wheel unit, and a support bracket disposed in a rear end region of the body frame for supporting a grass catcher for collecting grass clippings cut by the mower unit. With this construction, that is with the engine protruding by a reduced length rearward and a grass catcher supported at the rear of the body frame for collecting grass clippings, the lawn mower may have a reduced total length even when the grass catcher is attached thereto.
The lawn mower equipped with a grass catcher attached to the rear of the vehicle body may advantageously include a duct extending through the space between the left and right rear wheels for transmitting grass clippings from the mower unit to the grass catcher. A duct of sufficient size may be disposed in the utility space of sufficient height formed between the left and right rear wheels for rearwardly guiding grass clippings cut by the mower unit. Such a duct may extend, for example, over a minimum distance without possibility of interference with other components.
In a preferred embodiment of the invention, the grass catcher is supported by the body frame substantially rearwardly of the engine for connection to an end of the duct, and a lift link mechanism for vertically moving the grass catcher is disposed so as to cover opposite sides of the engine. With this construction, the lift link mechanism does not increase the longitudinal size of the vehicle body. As an additional advantage, the lift link mechanism prevents obstacles such as trees from contacting the engine during an operational run of the lawn mower.
The grass catcher must be raised high when unloading grass clippings at a high level such as a truck bed. As a suitable construction for this purpose, it is proposed that the lift link mechanism include a pair of right and left props erected on the body frame substantially laterally and forwardly of the engine, and lift links extending from upper positions of the props to the grass catcher, respectively.
Generally, the mower unit is vertically movably attached to the body frame. To ensure power transmission to the input shaft of the mower unit from a cutting power transmission mechanism regardless of a vertical position of the mower unit, a transmission shaft with a universal joint is used as a transmission element from the cutting power transmission mechanism to the input shaft. To drive the mower unit in this way, the cutting power transmission mechanism may be disposed rearwardly of the mower unit. However, where the lawn mower has the engine above and between the left and right rear wheels, the engine is close to the mower unit, allowing a short distance between the cutting power transmission mechanism and the input shaft of the mower unit. This would require a large flexion angle of the universal joint, resulting in a low transmission efficiency.
This problem is solved, in one preferred embodiment of the invention, by a cutting power transmission mechanism for transmitting cutting power from the engine to the mower unit, which includes a first power takeoff shaft extending along the body frame to a position forwardly of the mower unit, and a second power takeoff shaft extending along the body frame forwardly of the mower unit to have one end thereof connected to the first power takeoff shaft and the other end connected to the mower unit. In this construction, the second power takeoff shaft is disposed in a region forwardly of the mower unit where the engine imposes no positional restriction at in the fore and aft direction. Thus, the second drive takeoff shaft may be made sufficiently long to diminish the flexion angle of the universal joint.
Further, in the preferred embodiment of the invention, the drive transmission mechanism includes left and right transmissions allocated to the left and right rear wheels, respectively, and a distributing device for distributing drive from the engine to the left and right transmissions. In this construction, left and right transmissions may be arranged in the regions of the left and right rear wheels to divide a space for accommodating the drive transmission mechanism. This is advantageous in terms of space-saving design.
Other features and advantages of this invention will be apparent from the following description of an embodiment to be taken with reference to the drawings.